Origin

Late 15th century (in the sense 'clean, free from impurities'): from French net, from Latinnitidus 'shining', from nitere 'to shine'; related to net2. The sense 'bright' (now obsolete) was recorded in English in the late 16th century.

Neat came into English via French net, from Latin nitere, meaning ‘to shine’. It was first used in a sense quite similar to its main modern meaning, but with a greater emphasis on the handsome appearance of the thing described, as in this quotation from the 16th century, ‘O thou Jerusalem full faire…much like a Citie neat’. The sense ‘undiluted’, as in ‘neat whisky’, derives from the old use ‘free from impurities, clean’, first found in the late 15th century. The slang sense ‘excellent’ was American, from the beginning of the 19th century.

Origin

Neat came into English via French net, from Latin nitere, meaning ‘to shine’. It was first used in a sense quite similar to its main modern meaning, but with a greater emphasis on the handsome appearance of the thing described, as in this quotation from the 16th century, ‘O thou Jerusalem full faire…much like a Citie neat’. The sense ‘undiluted’, as in ‘neat whisky’, derives from the old use ‘free from impurities, clean’, first found in the late 15th century. The slang sense ‘excellent’ was American, from the beginning of the 19th century.